1. Technical Field
The present invention relates to a lighting apparatus that includes a power unit externally supplied with power and a light source to be lit with power supplied from the power unit and has a structure to control a light quantity of the light source on the basis of a control signal externally supplied.
2. Description of Related Art
In lighting apparatuses used for indoor/outdoor lighting, an incandescent lamp, a fluorescent lamp or the like is conventionally used as a light source. Since the brightness of a light emitting diode (hereinafter referred to as an LED) has been improved and a blue LED has been developed recently, a white LED obtained by combining a blue LED and a phosphor has been put to practical use, and accordingly, an LED having characteristics of compactness, small power consumption, a long life and the like is used as a light source for the lighting.
With respect to lighting apparatuses using conventional light sources, a lighting apparatus having a structure in which the light source may be dimmed in accordance with a control signal such as a dimming level control signal supplied from external equipment such as a dimming level controller is widely used. Also with respect to lighting apparatuses using LEDs as light sources, various lighting apparatuses having a structure in which the light source may be dimmed in accordance with a dimming level control signal supplied from external equipment have been proposed (see, for example, Japanese Patent Application Laid-Open No. 2007-234415).
A lighting apparatus disclosed in Japanese Patent Application Laid-Open No. 2007-234415 includes a power unit externally supplied with power and an emission unit to be lit with power supplied from the power unit, and the power unit controls the brightness of the emission unit in accordance with a dimming level control signal supplied from external equipment of a dimming level controller.